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/************************************************************************
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* This source code file is the property of MengHang.Li.
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* The contents of this file are intended for non-commercial use only.
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* No individual or organization may use this file for commercial purposes
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* without the explicit written permission of MengHang.Li.
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*
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* This source code is provided "as is" without any warranties. The author
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* or copyright holder shall not be liable for any consequences, direct or
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* indirect, arising from the use of this source code.
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*
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* Copyright Notice: (C) 2024-2025, MengHang.Li.
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*
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* File: led.s
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* Author: LMH
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* Creation Date: 2024.09.22
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*************************************************************************
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* LED 使用IO：GPIO1_IO03
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*************************************************************************/
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/** @group 外设时钟控制寄存器 - CCM_CCGRx
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  * @{
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  */
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.equ CCM_CCGR0_ADDR, 0x020C4068
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.equ CCM_CCGR1_ADDR, 0x020C406C
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.equ CCM_CCGR2_ADDR, 0x020C4070
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.equ CCM_CCGR3_ADDR, 0x020C4074
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.equ CCM_CCGR4_ADDR, 0x020C4078
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.equ CCM_CCGR5_ADDR, 0x020C407C
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.equ CCM_CCGR6_ADDR, 0x020C4080
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/**
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  * @}
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  */
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/**
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  * @brief LED IO 复用控制寄存器 - IOMUXC_SW_MUX_CTL_PAD_GPIO1_IO03
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  */
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.equ LED_MUX_CTRL_ADDR, 0x020E0068
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/**
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  * @brief LED IO 配置寄存器 - IOMUXC_SW_PAD_CTL_PAD_GPIO1_IO03
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  */
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.equ LED_PAD_CTRL_ADDR, 0x020E02F4
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/**
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  * @brief LED IO 数据寄存器 - GPIO1_DR
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  */
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.equ LED_GPIO_DR_ADDR, 0x0209C000
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/**
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  * @brief LED IO 方向寄存器 - GPIO1_GDIR
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  */
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.equ LED_GPIO_GDIR_ADDR, 0x0209C004
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/**
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  * @brief LED IO 亮灭控制掩码
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  */
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.equ LED_STATUS_ADDR, 0x00000008
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/**
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  * @brief 声明全局_start
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  */
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.global _start
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/********************************************************************
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* Function Name  : _start
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* Input          : xxx
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* Output         : xxx
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* Returns        : xxx
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* Description    : 裸机代码启动入口
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* Note           : 2024.09.22 By LMH
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**********************************************************************/
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_start:
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    /* 1、使能 CCM_CCGRx 时钟*/
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    LDR R0, =0xFFFFFFFF
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    LDR R1, =CCM_CCGR0_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR1_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR2_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR3_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR4_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR5_ADDR
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    STR R0, [R1]
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    LDR R1, =CCM_CCGR6_ADDR
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    STR R0, [R1]
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    /* 2、LED IO 复用为GPIO(Bit 0 ~ 23)*/
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    LDR R1, =0x00000005
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    LDR R2, =LED_MUX_CTRL_ADDR
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    STR R1, [R2]
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    /* 3、LED IO 配置
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        @ bit 16:0 HYS关闭
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        @ bit [15:14]: 00 默认下拉
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        @ bit [13]: 0 kepper功能
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        @ bit [12]: 1 pull/keeper使能
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        @ bit [11]: 0 关闭开路输出
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        @ bit [7:6]: 10 速度100Mhz
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        @ bit [5:3]: 110 R0/6驱动能力
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        @ bit [0]: 0 低转换率
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    */
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    LDR R1, =0x000010B0
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    LDR R2, =LED_PAD_CTRL_ADDR
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    STR R1, [R2]
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    /* 4、LED IO 方向设置为输出*/
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    LDR R1, =0x0000008
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    LDR R2, =LED_GPIO_GDIR_ADDR
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    STR R1, [R2]
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    /* 5、点亮LED 拉低有效*/
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    LDR R1, =0x00000000
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    LDR R2, =LED_GPIO_DR_ADDR
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    STR R1, [R2]
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/********************************************************************
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* Function Name  : loop
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* Input          : xxx
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* Output         : xxx
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* Returns        : xxx
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* Description    : 死循环
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* Note           : 2024.09.22 By LMH
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**********************************************************************/
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loop:
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  b loop

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led: led.o
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  # 命令1：编译生成led文件，-nostdlib 用于指定不需要标准库
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  # 因为代码中的_start 会和标准库中的冲突，会报错，裸机开发时必须指定
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  arm-linux-gnueabihf-gcc -nostdlib -o led led.o
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  # 命令2：链接代码，将代码放在0x87800000中运行，生成elf文件
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  arm-linux-gnueabihf-ld -Ttext 0X87800000 led.o -o led.elf
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  # 命令3：将elf文件转译成.bin文件
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  arm-linux-gnueabihf-objcopy -O binary -S -g led.elf led.bin
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  # 命令3：反汇编，用于检查代码正确性
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  arm-linux-gnueabihf-objdump -D led.elf > led.dis
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%.o: %.s
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  arm-linux-gnueabihf-gcc -c $<
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clean:
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  rm *.o
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  rm led
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  rm led.bin
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  rm led.elf
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  rm led.dis